Boring bugs pose threat to ash trees

Thomas E. Worthley, associate extension professor of forestry at the University of Connecticut, installs a "Barney Trap" designed to capture the emerald ash borer along Horse Pond Road in Salem on Monday. The insect is a wood-boring beetle that can be lethal to North American ash trees.

Though the emerald ash borer hasn't been found east of the Connecticut River yet, scientists are urging owners and caretakers of parks, yards and forests with ash trees in this part of the state to be on the alert.

"It's not a question of if, it's when," Gale Ridge, assistant scientist at the Connecticut Agricultural Experiment Station, said this week.

Ridge advised people to locate any ash trees on their properties so that if the presence of the invasive beetle is confirmed within 15 miles, the trees can be treated preemptively.

"They should be treated immediately," Ridge advised.

For trees smaller than 18 inches in diameter, insecticides containing imidacloprid can be applied to the root system, as long as the tree is not flowering, Ridge said. "For larger trees, people should get professional help," she added.

Thomas Worthley, assistant extension professor with the University of Connecticut Extension Center, said some property owners in infected areas are choosing to cut ash trees down ahead of any infestation and replace them with another variety.

To keep tabs on the ash borer's movements, the extension center is hanging 150 large, purple triangular-shaped traps on ash trees throughout eastern Connecticut, Worthley said. The extension center is working on the project with the U.S. Forest Service.

"We've hung about 50 to 100 so far," said Worthley, who was setting some of the traps Monday afternoon. The traps contain pheromone lures with a sticky surface that attract and capture ash borers. One of the traps was placed in Norwich near the intersection of Routes 2 and 32. Preferring moist soil, ash trees are often found along river and stream banks, helping filter pollutants out of runoff, Worthley said.

"We're setting the traps all over the eastern counties, where we find patches of stressed ash trees or randomly at locations identified on a grid," he said.

Since first appearing in Connecticut in 2012, the highly destructive invasive pest has spread to 15 towns in four counties in the western part of the state. It first appeared in the United States in the late 1990s and has since spread to 23 states thus far, most recently New Jersey. It has caused the destruction of millions of ash trees from Kansas to Michigan to New Hampshire to North Carolina.

Ash trees, which make up 4 percent to 15 percent of Connecticut's forests, were commonly planted along urban streets and in parks.

"It's a nice street tree," said Katherine Dugas, assistant scientist at the experiment station. Ash is used for baseball bats and basket weaving and is popular as fuel because it emits little smoke and can be burned without seasoning, she said.

Since the first infected trees were identified in Prospect, the state has enacted a quarantine on the movement of ash logs, ash nursery stock, ash materials and hardwood firewood from New Haven, Fairfield, Hartford and Litchfield counties.

Most of the infestation so far is concentrated in New Haven County, Dugas said. The ash borers invade the tree beneath the bark and feed on its conducting tissue, effectively strangling it within a few years, she said.

The Connecticut River will not be a barrier for them, she added. "These guys are free flying," she added, noting that they can also be carried by strong winds and in firewood, which is the reason for the quarantine.

"If you're bringing firewood from one of the quarantined areas to your favorite campground, you could be dropping potential invasive pests in your favorite campground," she said. "And as you're driving around, you could be releasing a trail of emerald ash borers."